This invention relates to compositions in the form of liquids, sprays, gels, and pastes, which remove dried-on and cooked-on food and other difficult-to-remove soils from kitchen utensils, flatware, dishes, glassware, cookware, bakeware, cooking surfaces, and surrounding areas in a convenient, easy, timely, and mild manner.
Of the difficult-to-remove soils, the most severe is the baked and/or burned-on (especially when reheated and/or allowed to build up over time). These are very difficult to remove, without using severe methods including heat and alkali. But there is another category of soils that is also a problem especially in automatic dishwashing. Soil categories include grease, meat (including skin), dairy, fruit pie filling, carbohydrate, and starch. Soiled substrate categories include aluminum, iron, stainless steel, enamel, plastic, Corningware, Pyrex, and other glass cookware.
When people wash dishes by hand, these difficult soils are individually treated using assorted household detergents, especially light duty liquids, and lots of mechanical action. When people use a dishwasher, these tough soils require extensive pretreatment, almost to the point of completely washing the dish before putting it in the dishwasher. Pretreatment is required because of the mechanical deficiencies of the dishwashers and because people dislike having to rewash dishes because they did not come clean the first time. The use of light duty liquids for the purpose of pretreatment is inconvenient because the surfactants are very foamy and highly unsuitable for use in an automatic dishwasher. They must be rinsed off completely before putting the items in the dishwasher. It is possible to use automatic dishwasher detergent for pretreating items to be washed by a mechanical dishwasher. Deficiencies of this method revolve around the caustic and highly oxidizing nature of conventional autodish detergents which usually contain hypochlorite bleach releasing agents and alkali. Thus autodish detergents, whether dissolved or in a slurry form, are dangerous, caustic, attack surfaces and release fumes.
People use all sorts of tools and substances to pretreat their dishes. Examples include sponges, brushes, towels, steel wool, nonwoven plastic or fiber scrubber pads, copper mesh scrub pads, plastic mesh scrub pads and the like. They also use various substances including light duty liquid dish detergent (such as Dawn.RTM., Palmolive.RTM., Ajax.RTM., Joy.RTM. or Lux.RTM.), ammonia, bleach, table salt, washing soda, baking soda, and commercial hard surface cleaners (for example Fantastic.RTM., Ajax.RTM., or 409.RTM.). The physical methods are a lot of work. The light duty liquid detergents are formulated to have high foam levels. They require complete and careful rinsing before putting any item washed with them into the dishwasher. Ammonia and bleach can be corrosive and dangerous to people and to the household items and surfaces. Table salt, washing soda and baking soda by themselves are not effective on many types of tough soil.
It is possible to use a specially formulated pretreatment composition based on surfactants, polyhydric alcohols and a thickener such as described in U.S. Pat. No. 4,818,427. This material does not take advantage of the catalytic power of enzymes and requires a relatively long soaking time, preferably at least 30 minutes.